This is about my VW Polo (mk4). It's been a cat C in the past after taking a knock to the front bumper.
It needs the coolant topping up every six weeks (ish). I've been carrying a bottle of water in the car for this reason. It takes about 75cl to top it up to max when it's empty. When it happens the engine temperature warning light comes on (red) on my dash after driving for two minutes and the level is below minimum. I've been keeping an eye on the coolant level, it can be on max for weeks, then suddenly below minimum.
I've had it in the garage in the hope they can find a leak, or a crack. They say it's sealed tight with no damage or leaks that they can find. My radiator is in good condition. It's not smoking from the exhaust, so I don't think I'm burning it off. Removing the oil cap - the underneath is not white or milky.
Is there anything I can do? I'd rather not take it to the dealers for diagnosis, but it looks like I'm going to have to now.